A corpora



July 5, 1927.

J. W. CRUIKSHANK APPARATUS FOR GRADING SAND AND GRINDING GLASS Filed May5, 1922 v 4 Sheets-Sheet l INVE NTOR July 5, 1927; 1,634,254

J. W. CRUIKSHANK APPARATUS FOR GRADING SAND AND GRINDING GLASS Filed May5, 1922 4 Sheets-Sheet 2 my M July 5 1927. L634,254

J. w. CRUIKSHANK APPARATUS FOR GRADING SAND AND GRINDING GLASS Filed May5, 1922 4 sheets-sheet 3 O a} N III/11001111111110]; w

July 5, 1927. V 1,634,254

J. w. CRUIKSHANK APPARATUS FOR GRADING SAND AND GRINDING'GLASS Filed May5. 1922 4 Sheets-Sheet 4 INVENTOR Patented July 5, 1927.

UNITEDSTATES PATENT OFFICE.

JAMES W. CRUIKSHANK, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO J. W.CRUIK- SHANK ENGINEERING COMPANY, OF PITTSBURGH, PENNSYLVANIA, ACORPORA- TION OF PENNSYLVANIA.

APPARATUS FOR GRADING SAND AND GRINDING GLASS.

Application filed May 5, 1922. Serial No. 558,743.

My invention. relates broadly to sand grading and more particularly tothe art of grinding and polishing plate glass, and to an apparatus forgrading and supplying abrasive material for the grinding operation.

A particular object of the present invention is to provide a simple andeflicient apparatus for the purpose of furnishing suificiently finegrades of sand for the finishing operation of grinding the glass, and atthe same time utilizing all the sand applied as abrasive with a minimumloss of overflow.

Another object of the invention is to provide a medium coarse grade ofsand free from the larger grains such as usually found in the roughsand.

A further object is to apply the abrasive with the proper admixture ofwater. involving the elimination of all surplus water.

Still another object of the present invention is to both grade andsupply the fine sand in a novel manner by which the efiiciency of theapparatus is increased, and the operating steps decreased.

The foregoing and. other objects of the present invention, together withtheir attendant advantages will be clearly apparent as the inventionbecomes better understood by reference to the accompanying specificationand drawings forming apart thereof. In these drawings, which areillustrative only of a preferred embodiment of my in rent-ion in whichchanges may be made in the construction and operation without departingfrom the spirit of my invention or scope of my broader clai1ns,

Figure l is a plan view showing the grading apparatus in connection withthe plate glass grinding machine;

Figure 2 an end elevation of the con struction illustrated in Figure 1:

Figure 3 is sectional elevation on the line TIL-III of either Figure 1or Figure 2;

Figure 4 is a detail section illustrating one form of overflow weirwhich I may use; and

Figure 5 is a diagrammatic view illustrating successive operations.

In the process of grinding glass in a plate glass grinding machine. acoarse grade of silica sand is applied directly to the glass laid on alarge revolving table over which are mounted disks which are free torevolve. The lower surfaces of these disks, adapted to contact with theglass to be ground, are covered with cast iron plates or shoes. The sandis applied with water and passes under these cast iron shoes by which itis ground down on the surface of the glass. These grains when crushed onthe glass surface chip out fragments of glass and thus grind thesurface. The resulting surface from grinding with coarse sand presentsnumerous holes between sharp serrated ridges, these holes being of anappreciable depth. In order to produce a smoother surface, finer gradesof sand must be successively applied. In order to get good results amedium coarse grade of sand must be applied to reduce the depth of theholes and take off the tops of the projections or what is technicallyknown in the art as taking out the bottoms. After the application ofthis medium coarse sand, a very fine grade of sand must be applied whichwill further reduce the inequalities of the surface. By an examinationwith the microscope it will be found that what appears to the eye to beextremely fine particles of sand are, in reality, much larger intheirlinear dimensions than the width and depth of the irregularities on thesurface of the glass. It good work is to be done in obtaining a surfacethat is capable of receiving a quick polish by the polishing machine,the last sand must be of an extremely fine grade. This will prepare theglass for the production of the final smooth in which an extremely finegrade of emery or other relatively hard abrasive is used for roundingoff the tops of the serrated projections produced by the sands.

From the foregoing it will be apparent that it is necessary not only toproduce a very fine grade of sand, but also that the finest grains ofsand are useful and should be retained and reused on the grindingmachine and not allowed to get away through the overflow of the gradingapparatus. In this art the quantity of sand used for the grindingpurpose is very large, and any saving effected in the use of thismaterial is of great economical. importance and highly desirable.

In sand graders of the horizontal flow single grinding machine iscirculated, difiiculty has been experienced in p1;-'oduc1ngfine enoughgrades of sand for the finishing operati on due to the comparativelylimited, sp not available. at the. machine after thepcoarser grades-ofsand had been applied and clrculated on each machine, to the finesand-pits. These plts are of considerable length and width so that it ispossible to 'o'btain'a very fine grade 033 sand .irorn them.

'By the present inventionlfam able to considerably reducethetotal':amount ol 'sand required; to produce the necessary medium coarse; sand;and to save and'grade the fine sands whereby they may be easily andveiliciently utilized: 1 c I: Referring more parlncularlgz in thedrawwings; there =-isillwdtated in outline-the usual V 1 table "b abovel1 .are supported runne s72" on suitable bridge beams 315' The tablel-1s surrounded 1 jbyfifa *ditca tot any desired: construction adaptedto discharge through; a trough 5 intoasump; 6:; Fromv this sump the sandanclrwaten are elevated by means of an air- 7 lowthe water level is anoutlet '23, which is.

lift pump; 7; disoliarginginto a hopper 8 communicating with the'to'p rofe a pit 9tor breaking the force ofthe-flow into the pit 95';Ftdrnthepit '9 an air-litt pnmpLO; is

iadapteclwto raise" the sand and: waten and deliver the same directlytothe grinding table. c

" 11 leading to suitable sewer-connectionsand with anoutlet:12*dischanging into mpit Materialis raised from the pit 113 bya suit}-able airlift pump 14h tllfiehalglfig" at, its upper-end into-a1 hopper15. The'hoppen15 supported above a ant-:diun coarse sand ho: 16 andisHadapted to discharge? its contents thereinto 1 through a bottomopening 1 17. Th e box;- "16 is; elevated above the grinding table1and-isprovided with an" outlet 18 controlled- -by a valve lll an'dadapted. to disch-a-irgethe'contents of the box 16- intov the troughQOileadi-ngtjO the center ot the grind-- ing table 11 A waterjet 211'splaced in the bottomot thefbox-le and is controllable by means o l? avalve 22, whereby thecontents ot the box maybe agitated at will.Connn-u-ni-. eating with the medium coarsesand box. 16 above the levelof the sand ,therein andf benormallv closed bv'a-remoaiableplug 24c. I

I At the end of the-medium coarse sand box ldop positei that fromwhichthe sand and water are deliveredthereto is arrangedra trough25iforminga-weir over which a portion of the sand and water flow.Ilhisoverflow is conducted hy a trough 26 toabox 26 havingits bottom atthe level of the water in a concentrator 27; This box is provided i Theold method, ofproducing the fi'ne'sand's wasjto take the overflow fromall the gr nding machines,

witlra bottom opening delivering the water a-ndj sand to theconcentratorat the lev'elol thewater therein. This concentrator isprovidediwith. ahopper shaped bottom 28, having. aibottoin outlet pipe29whithidischarges into the" pit 1 3 which'suppli'es. theair lift v pump14.

By reason of; the oonstnnction described it will be apparent 'that theair-lift pump 14 delivens. medium coarse andrfinje sand to the box 16.During the passage of the Water through this boxthe coarser grains'o'fxsand are deposited, but as theho-X is relatively small, a largequantity of sand that is too coarse to make the finest grade passesthere-' through into theconoentrator. 'This' sand is deposited in theconcentiator, and passes therefrom through :t'hebottom connection 29;to: the pit 113, from which it is again raisedrby the sand! pumptothebox 16. This 7 concentrator is ieii'ective For continually re.

delivering the coarser sand touthe box 1 6 until there "accumulatestherein thBfdBSll'Qd quantity of medium coarse sand. TheroncentratorQTJmay beprovided with awater jet 30 controlledby afvalve 31,whereby-the sand" may be loosened fin clogged therein.

At the opposite end ofthe concentrator from whichit .receives its supplyof sand and water, there: may be formed an; overflow Weiror troughr32,having an outlet, 33

of relatively fixed-area: in; the bottom thereof, delivering to a trough34-; whichin turn supplies, a. hopper 35. It will be apparent case itbecomes" that due to the action} of the concentratoin only the finergrades :of sand pass through the outlet 33, into the trouglr34,-Theooncentr-ator 27 maybeprovidedwith an oven flow adjacent oneendithereon"; andbommunica ting there\ vithbelow thelevelflof the edge ofthe trough 32-bit at a-l'evel: higher than that o'l 'thei outletfiilaThis overflow may be connected in" any desired manner to the sewer.

there is provided a vertically extending screen 38, \Yl'lJlG- ihhfhfl dscharge; end there is provided sin'iilarly arranged screen f The screenplate 38: is provided with numherof holes proportioned 1n such mannerthatthe flow through the rader will be-thc fullwidth of the hon andof;the same depth This forms what is as the screen plate. knownas awhole-current? at ther'upper .part uof the box.v The correspondingscreen f 39 may be formed withithe; same number of holes, whereby thecurrent will? boot the same depth and intensity as whenit is first"admitted through the screenplate38. As

ill

beitore stated, the outlet 33 from the concentrator has a relativelyfixed area, Whereby the flow through the sand grader may be given avelocity su'liiciently slow to insure the deposit therein of the veryfine grades of sand delivered thereto by the concentrator. It will beapparent that by changing the relative size of the outlet 33, thegrading of the sand in the sand grader may be, correspondingly varied.

The level in the grader 36 is controlled by an overflow weir from whichthe water may pass to the sewer through a suitable connection 41.

The usual form of grader has several separate compartments, each ofwhich is adapted to receive sand of a difl'erent grade. Each of thesecompartments has to be separately washed out, thereby entailingconsiderable more labor. This results in decreased efficiency. This isovercome by construetin a grader as pointed out hereinafter. idjacentthe inlet end of the grader there is also provided a single outletopening 42 adapted to be closedundcr normal conditions by a removableplug 4.3. This outlet 12 leads to a: trough 14 adapted to deliver sandto the grinding table 1. At intermediate points throughout the length ofthe grader, there may be provided overflow sewer outlet connectionsadapted normally to be closed by removable plugs 46. The grader hereinprovided is. formed without any intermediate divisions or battlesbetween the current controlling screens. This is true for the reasonthat in a grader of this type the sand settles from suspension in thewater carrying it in accordance with the velocity of the current throughthe grader and in proportion to the size of the individual grains. Ihave found that the sand deposited at the end of a compartn'icnt towardthe inflow of the current is coarser than that at the opposite end. Thelarger grains will. settle rapidly and the smaller grainsproportionately slower, the speed of settlement, subject tomodifications such as the shape and term of the grains, varies as thesquare of the linear dimensions otthe grain so that the larger particlessettle rapidly at the receiving end of the grader and the lighterparticles are carried to the other end. In a grader of this type thegrading will vary tl'u'oughout the length thereo'l starting with acomparatively heavy sand at the receiving end and ending with a veryline sand adjacent the discharge end. The screens, and the proportioningof the outlet 33, equalize the How and break up the surface currentcausing a uniform travel. of water the full width of the box andthroughout a depth determined by the height of the screens. Such agrader considerably sim-, plifies the work of the operator as will bemore telly set forth hereinafter. LA

jet 21 controlled by the valve 22.

The operation of a construction such as herein described is as tollowsz-The water, together with the sand, passes from the grinding table to theditch 4t and thence to the sump 6, from which it is elevated to the pit9 by the pump 7. The coarser grade of sand descends to the bottom ofthis pit, while the water carrying the finer particles passes throughthe outlet 12 to the pit l3, trom which it is in turn ele vated by pump14 to the medium coarse sand box 16. This water and the finer sand passthrough the box 16 while the coarser sand is deposited on the bottomthereof. The water carrying the finer particles of sand flows out overthe weir termed by the trough 25 to the concentrator. The currentpassing through the box 16 is somewhat rapid, and a quantity of thecoarser sand will be carried over to the concentrator. This heavy sand,together with a quantity of the finer sand, settles downwardly to thebottom of the concentrator, and is redelivered to the box 16 by pipe 29and pump 14 where the coarser sand will again have an opportunity ofbeing retained. The flow through the pipe 29 into the'pit l3 and thenceby means of the pump 14 to the box 16 in a concentrated. form having alarger percentage of sand than originally contained in the Waterentering the medium coarse sand box. By this means a quantity of mediumcoarse sand will be deposited in the bottom of the box 16 readytobedelivered to the grinding machine at the desired time during theoperation thereof. The remainder of the water passing into theconcentrator 27 will flow over the edge of the trough 32, part of itpassing through the outletto the grinding box 37 and the remainder byoverflow 33 to the sewer. The part of the outflow through an o'l ieningof predetermined area from the concentrator passes to the grader throughwhich there is produced a tlow as described. As the grader has nodivisions or bafiies therein, but is a trough of uniform cross sectionalarea with a hopper bottom, the sand is deposited in a graded term, theheavier particles being tound at the intake and the lighter ones at theoutflow end. This is highly desirable.

The operator, in manipulating the apparzn tus. first shuts off the pump10 delivering sand from the pit 9 to the table, and prepares to deliverabrasive from the medium coarse sand box 16 to the table. He there foreshuts down the pump 14 which stops the flow into this box. The plug 24is then drawn. allowing the surplus water from the upper portion of thebox to flow to the sewer and leave in the box a solid deposit of sand.Water is then forced into this sand by the This loosens the sand andstarts it through outlet 18, valve 19 having been opened, and

ill;

ll ll 5 until. allot thcisand is Washed out'oi: the

trough: 20, to the grindi-ng tablc. soon as the sand startsetheoperator: follows up Wit'ha hose givingjust the right consist- 'ency oiWaterto -the' 'sand to produce the best results i'ngrinding. The-hose isused box. Y v The linersand-deposited in thcgra der 36 is then utilized.T he plugs 46 are first'withdrawn to permit the escape of the surplusWaterabove the sand, then plug 43' is with? drawn allowing the sand topass through trough 4am the grinding machine. 'This sa-nd is very-fineand almostcolloidal in its nature, and requ res Washing from the box by;means of-a stream of water. As there is but a single outlet opening andonly one main compartment, the work oftheoperator is reduced to aminimum. The' operator first Washes out" thesand' de iosited' around theoutlet 42 with thehose after thesurplns waterhasfbeenremoved; and thenall the sand at the head end ofthe box following gradually With the hoseto thetail end where the finest grade of sand is deposited." This givesaperfect and continuous fsequenceot the finer grades for the smoothingoperation, and at the-sametime enables .the'quantity of 1 Water suppliedwith the abrasive to be acreceiving sandtheretrom, means torired'eliv'ering the coarse portionof said sand to the grinding machine,-othermeans for delrver- 65 ing the medium coarsea'nd finer portionsofcurately controlled to; prevent an obj actionable excess. This'is verydesirable in the grinding. ofplate glasa-as 1t insures the gradualsmoothing thereot by sand grains,

gradually decreasing in, size, as disliinguished by the periodic orintermittentteed forpredetermined intervals dependent upon the sizes ofthe compartments, of successive grades of sand friom successivecompartments."

The subject matter disclosed herein with respect to the process offeeding the graded material to the grinding machine, as originallyrcovered in claims 9*to'12 ,-both inclue sive, is covered by mydivisionalapplication SerialrNo. 142,628 filed October 19, L926.

From the foregoing it will be apparent that I lnweprovidedapparatus byineans of Wh1Cl1 it is possible tosupply' SUQCBSSIVG grades of sand-tothegrinding table inan eflicient manner-(most of-the fine sandbeingretained and utilized in the grinding opera [Iain also enabled tocontrol. the amount of Water passingfi with the sand to the grindingtable, At the same time, the number of? operations is: greatly reduced;These constitute important features; and-advantages of the presentinvention. l

I claim:

1. In a sand grading apparatus for: plate.

glass grinding machines, the combination With the grinding .machine,of'means tor glass grinding machines, the combination With the grindingmachine, of means-tor re; ce ving sand therefrom, meansfor redehven ingthe coarse portion of said sand to the 5 j a portion of the mediumcoarse-sand isretained, concentrating means for increasingthe amount ofmedium coarse sand deposited in said box, and meansi'or receiving sand:from the concentrator and grading the same, said last mentioned meanscompris ng a" grinding machine, means for deliveringthe 'medlum coarseand finer portlons of sa d 7 'sand; to a medium coarse sandbox whereingradinglbox free from intermediateq partilt onsiand provided withmeansfdrproduti- I ing a Whole current therethrough, substan}. i

tially as described.

3. Inf a sand grading apparatus for-plate glassgrindingsmachgines, thecombination with the grinding machine, of means for re: ceiving sandtherefrom, means for redehver,

ing aportion OfSflid SanCl to the grinding."

machine, amedium coarse sand box-,lineans for repeatedly redeliveringpart off the? eimaining portion of said sand to said .b wherebythecoarser particles are retained therein, and. means forgrad-ing thenfinerparticles of the'sand, substantiallyg-asi described.

4:; In a sandgrad-ing apparatus glassi grinding machines, thecombination 'With the grinding machine, of means for re;

ceiving sand therefrom, a medium coarse sand box, a concentrator, "and;grading box, said means,med1um coarse sandbox,

concentrator and? grading box having opera-p rive: connectionstherebetween; for success sively delivering sand to effect gradingvthereof, and means for supplyingthe' graded sand from saidmedium coarsesand box and 1 sai'dgradingibox, substantially as described; 5. In asand grading apparatus'forplatc glass grinding machines,thewcombin'ation' with a' grinding machine, of, a medium} coarse sandboX, means for ,del1ver1ng-.sand j from the grinding m achi neito said.medium coarse sand box, a concentrator cooperating with said 1 box forsuccessively redeliverin-g sand thereto to effect separation in saidboxof the medium coarsersand particles, and

meansfor delivering said sand from the medium coarse sand box to thegrinding machine, substantially as described.(

6. In a sandlgrading apparatus-for plate glass grinding 'IIlELChlllQS',the combination with a? grinding machine, of a medium coarse sandbox,means for delivering sand from the grinding machine to said mediumcoarse sand box, a concentrator cooperating with said box forsuccessively redelivering sand thereto to edect separation in said boxof the medium coarse sand particles, means for delivering said sand fromthe medium coarse sand box to the grinding machine, a grading boxreceiving a portion of the overflow from said concentrator, and meansfor delivering sand from the grading box to the grinding machine,substantially as de scribed.

7 In a sand grading apparatus for plate glass grinding machines, thecombination with a grinding machine, of a medium coarse sand box, aconcentrator and a grader, means for delivering sand from the grindingmachine to said box, means for delivering a portion oi said sand to saidconcentrator, operative connections between said concentrator and saidfirst mentioned means whereby a portion of the sand from saidconcentrator is redelivered to said box, and means for conducting thefiner grades of sand from r said concentrator to said grader,substantially as described.

8. In a sand grading apparatus for plate glass grinding machines, thecombination with a grinding machine, of a medium coarse sand box, aconcentrator and a grader, means for delivering sand from the grindingmachine to said box, means for delivering a portion of said sand to saidconcentrator, operative connections between said concentrator and saidfirst mentioned means whereby a portion of the sand from saidconcentrator is redelivered to said box, and means for conducting thefiner grades of sand from said concentrator to said grader, said graderhaving an unobstructed intermediate portion and having means forproducing a whole current therethrough, substantially as described.

9. In a sand grading apparatus for plate glass grinding machines, thecombination with the grinding machine, of means for receiving sandtherefrom, means for redelivering the coarse portion of said sand to thegrinding machine, other means for delivering the medium coarse and finerportions of said sand to a medium coarse sand box wherein a portion ofthe medium coarse sands is retained, concentrating means for increasingthe amount of medium coarse sand deposited in said box without passageto the grinding machine, and means for receiving sand from theconcentrator and grading the same, substantially as described.

10. In a sand grading apparatus for plate glass grinding machines, thecombination with the grinding machine, of means for resand to a mediumcoarse sand box wherein a portion of the medium coarse sand is retained,concentrating means for increasing the amount of medium coarse sanddeposited in said box without passage to the grinding machine, and meansfor receiving sand from the concentrator and grading the same, said lastmentioned. means comprising a grading box tree from intermediatepartitions and provided with means for producing a whole currenttl'lGI'GilhI'OUgl'l, substantially as described.

11. In a sand grading apparatus for plate glass grinding machines, thecombination with the grinding machine, of means for re ceiving sandtherefrom, means for redelivering a portion of said sand to the grindingmachine, a medium coarse sand box, means for repeatedly delivering partof the remaining portion of said sand to said box independently of thegrinding machine, whereby the coarser particles are retained therein,and means for grading the finer particles of the sand, substantially asdescribed.

12. In a sand grading apparatus for plate glass grinding machines, thecombination with a grinding machine, of a medium coarse sand box, meansfor delivering sand from the grinding machine to said medium coarse sandbox, a concentrator cooperating with said box for successivelyredelivering sand thereto to ettect separation in said box of the mediumcoarse sand particles, without repassing the same to the grindingmachine, and means for delivering said sand from the medium coarse sandbox to the grinding machine, substantially as described.

13. In a sand grading apparatus for plate glass grinding machines, thecombination with a grinding machine, of a medium coarse sand box, meansfor delivering sand from the grinding machine to said medium coarse sandbox, a concentrator cooperating with said box for successivelyredelivering sand thereto to eifect separation in said box of the mediumcoarse sand particles independently of the grinding machine, means fordelivering said sand from the medium coarse sand box to the grindingmachine, a grading box receiving a portion of the overflow from saidJAMES IV. CRUIKSHANK.

